Electric motor



y 9, 1940- E. c. GUED'ON 2,207,251

ELECTRIC MOTOR Filed July 50, 1938 Jnnmtor attorney Patented July 9,1940- PATENT OFFICE ELECTRIC MOTOR Emile C. Guedon, Audubon, N. 1.,assignor to Radio Corporation of America, a corporation of DelawareApplication July so. 1938, Serial No. 222,167

4 Claims. (01.172-36) mitted from the frame to the turntable mounted.

on the spindle and the record supported thereby, inasmuch as the bushingwithin which the spindie rotates is carried directly by the hub. Thetransmission of such vibrations is partly responsible for the productionof what is known as "rumble, with the resulting distortion of thereproduced sound.

The primary object of my present invention is to provide an improvedsynchronous motor wherein the foregoing difliculty is eliminated.

More specifically, it is an object of my present invention to provide animproved motor wherein mechanical vibrations in the frame will not betransferred to the turntable and the record supported thereby at thetime, of reproduction.

A further object of my present invention is to provide an improvedsynchronous motor of the type set forth which is'inexpensive ofmanufacture, which readily lends itself to rapid quantity production,and which is highly efflcient in use.

In the copending application of Gregory W. Blessing and myself, filedNovember 5, 1937, Serial No. 172,886 (now Patent No. 2,157,158, grantedMay 9, 1939), there is disclosed and claimed, among other things, amotor of the type here under consideration wherein the turntable iscoupled to the rotor element by means of a plurality of resilientcoupling devices capable of absorbing any slight mechanical vibrationsoriginating in the motor without transferring them to the turntable.According to my present inven-- tion, I interpose a rubber sleevebetween the frame hub and the bushing which carries the turntablespindle. This further reduces and minimizes the possibility of rumble bypreventing motor vibrations from reaching the reproducing pickup whichcontacts the record.

The novel features that I consider characteristic of my invention areset forth with particularity in the appended claims. The inventionitself, however, both as to its organization and method of operation,together with additional objects and advantages thereof, will best-beunderstood from the following description of one embodiment thereof,when read inconnection with the accompanying drawing, in which thesingle figure is a central sectional view of a motor ac- 5 cording to mypresent invention.

Referring more particularly to the drawing, I have shown a motorcomprising a frame i provided with a hub 3 in which a bushing 5 is re.-ceived, the upper end of the bushing 5 extending l0 beyond or above thehub 3 and being secured to a laminated stator 9 of the type more fullyset forth in the above identified Roys patent. Surrounding the stator 9and cooperatively associated therewith is an annular rotor ll carried bya spider 13 which is fixed to the upper end of a spindle or shaft l5mounted for rotation in the bushing 5 and resting upon a thrust hearingI? seated in a depression IS in the bushing 5. A record supportingturntable I8 is connected to the spider I3 by means of a plurality ofpins 20 and resilient coupling members 2|, in a manner more fully setforth and claimed in the above identified copending application ofBlessing and myself. The turntable I8 is provided with a record center-245 ing spindle 23 which may be threaded into the upper end of the shaftl5 and which is insulated from'the turntable l8 by means of a rubberbushing 25, the spindle 23 preferably also being provided with a rubbersleeve 21, all as more fully described and claimed in the aforesaidcopending application to prevent vibrations arising in the motor fromreaching the pickup (not shown).

To further prevent vibrations originating in the motor from reaching theturntable and record 85 supported thereon with which the pickup is coop-I eratively associated, I interpose a soft rubber sleeve 29 between thehub 3 and the bushing 5. Preferably, however, I also interpose ametallic bushing or sleeve 3| between the rubber sleeve 29 40 and thebushing 5 to act as a bearingsurface for the bushing 5 when'the latteris'caused to oscillate by slight oscillation of the stator 9, as ischaracteristic ofthis type of motor. It will be noted from the drawingt'natthe rubber sleeve 28 5 completely isolates the bushing 5 with itsshaft l5 and all the parts carried thereby from the .hub} of the frameI, thereby serving effectively to prevent the transmission of mechanicalvibrations between thehub 3 and the bushing I.

Although I have shown and described but one modification of myinvention, itwill, no doubt, be readily apparent to those skilled in theart that many modifications thereof are possible;

, For example, in place of the rubber sleeve 29, an 5 oil saturated feltsleeve may be employed. Other changes will, no doubt, readily suggestthemselves to those skilled in the art, and I therefore desire that myinvention shall not be limited except insofar as is made necessary bythe prior art and by the spirit of the appended claims.

I claim as my invention:

1. In an electric motor, the combination of a supporting frame includinga hub, 'a bushing within said hub extending beyond one end thereof, aspindle rotatable in said bushing; a supporting'device carried by saidspindle for rotation therewith, a stator mounted on the extension ofsaid bushing, a rotor also carried by said spindie and cooperativelyassociated with said stator,

and means interposed between said hub and said bushing for preventingmechanical vibrations from being transmitted from said frame to saidsupporting device.

2. in an electric motor, the combination of a supporting frame includinga hub, a buslnlns, Within said hub extending beyond one endthereof,aspindle rotatable in said bushing, a supporting device carried by saidspindle for rotation therewith, a stator mounted on the extension ofsaid bushing, a rotor also carried by said spindle enemas andcooperatively associated with said stator, and

resilient means interposed between said hub and said bushing forpreventing mechanical vibrations from being transmitted from said frameto said supporting device.

3. In an electric motor, the combination of a supporting frame includinga hub, a bushing within said hub extending beyond one end thereof, aspindle rotatable in said bushing, a supporting device carried by saidspindle for rotation therewith, a stator mounted on the extension of,said bushing, a rotor also carried by said spindle and cooperativelyassociated with said stator, and a sleeve of soft rubber interposedbetween said hub and said bushing for preventing mechanical vibbrationsfrom being transmitted from said frame to said supporting device.

i. The invention set forth in claim 3 charac terized in that said statoris subject to slight osciliations, and characterized further by theaddition of a metal bearing sleeve interposed between said rubber sleeveand said bushing to act as a bearing surface for said bushing uponoscillation of said stator.

- s C. GUEDON.

